Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Sep;27(37):2200697.
doi: 10.2807/1560-7917.ES.2022.27.37.2200697.

COVID-19 mRNA vaccine effectiveness (second and first booster dose) against hospitalisation and death during Omicron BA.5 circulation: cohort study based on electronic health records, Portugal, May to July 2022

Irina Kislaya  1   2 , Ausenda Machado  1   2 , Sarah Magalhães  3 , Ana Paula Rodrigues  1 , Rafael Franco  3 , Pedro Pinto Leite  4 , Carlos Matias Dias  1   2 , Baltazar Nunes  1   2
Affiliations

COVID-19 mRNA vaccine effectiveness (second and first booster dose) against hospitalisation and death during Omicron BA.5 circulation: cohort study based on electronic health records, Portugal, May to July 2022

Irina Kislaya et al. Euro Surveill. 2022 Sep.

Abstract

We measured vaccine effectiveness (VE) against COVID-19-related severe outcomes in elderly people in Portugal between May and July 2022. In ≥ 80 year-olds, the second booster dose VE was 81% (95% CI: 75-85) and 82% (95% CI: 77-85), respectively, against COVID-19-related hospitalisation and death. The first booster dose VE was 63% (95% CI: 55-70) in ≥ 80 year-olds and 74% (95% CI: 66-80) in 60-79 year-olds against hospitalisation, and 63% (95% CI: 57-69) and 65% (95% CI: 54-74) against death.

Keywords: COVID-19-related death; COVID-19-related hospitalization; Omicron BA.5; SARS-CoV-2; Vaccine Effectiveness.

PubMed Disclaimer

Conflict of interest statement

Conflict of interest: None declared.

References

    1. Direção-Geral da Saúde. Norma 02/2021 - Campanha de Vacinação Contra a COVID-19 - Dose de Reforço. [Standard 02/2021 - Vaccination campaign against COVID-19 – Booster dose]. Lisbon: Direção-Geral da Saúde; 2021. Portuguese. Available from: https://www.dgs.pt/normas-orientacoes-e-informacoes/normas-e-circulares-...
    1. European Centre for Disease Prevention and Control (ECDC), European Medicines Agency (EMA). COVID-19 : Joint statement from ECDC and EMA on the administration of a fourth dose of mRNA vaccines. EMA/204784/2022. Stockholm: ECDC, Amsterdam: EMA; 2022. Available from: https://www.ema.europa.eu/en/documents/public-statement/covid-19-joint-s...
    1. European Centre for Disease Prevention and Control (ECDC), European Medicines Agency (EMA). COVID-19 : Updated joint statement from ECDC and EMA on the administration of a fourth dose of mRNA vaccines. EMA/635144/2022. Stockholm: ECDC, Amsterdam: EMA;2022. Available from: https://www.ema.europa.eu/en/documents/public-statement/updated-joint-st...
    1. Nunes B, Rodrigues AP, Kislaya I, Cruz C, Peralta-Santos A, Lima J, et al. mRNA vaccine effectiveness against COVID-19-related hospitalisations and deaths in older adults: a cohort study based on data linkage of national health registries in Portugal, February to August 2021. Euro Surveill. 2021;26(38):2100833. 10.2807/1560-7917.ES.2021.26.38.2100833 - DOI - PMC - PubMed
    1. National Institute of Health (INSA) Doutor Ricardo Jorge. Genetic diversity of the novel coronavirus SARS-CoV-2 (COVID-19) in Portugal. 23 August 2022 report. Lisbon: INSA; 2022. Available from: https://insaflu.insa.pt/covid19/relatorios/PORTUGAL_INSA_SARS_CoV_2_GENE...